Chrome only: Need to get back to a tab that you closed down a while back, with its contents intact? You could hit Ctrl+Shift+T until your fingers get sore, or open Sexy Undo Close Tab and search or click for your tab.

Sexy Undo Close Tab covers that one function and does it well, keeping track of a number of tabs you control (20 is the default) and making them easy to get to. On top of that, its options give you some other goodies, too, like changing the undo-tab-close to Ctrl+Z, mixing up the fonts, and customizing how your icon and list are displayed.